Mr Sefton could not break the figures down to individual towns but said a portion of the increase in Rotorua could be due to the fact that an office was set up in the city in August last year.
He said Rotorua businesses had been able to use the agency's services for the past four years but the number of companies using the drug testing service had increased since the Rotorua office had opened.
Mr Sefton said the increase in workplace drug testing couldn't be linked to increased drug use. He attributed the spike in testing to companies recognising the benefits of running a drug testing programme, not just in terms of safety but also employee morale and productivity.
However, he said up to 10 people a week were using various methods to try to cheat the test with most of them having a friend provide a clean urine sample.
"This is usually concealed down the donor's pants in small bottles, condoms or similar receptacles."
Mr Sefton said the level of cheating depended on the type of industry, but most occurred at pre-employment tests.
"The donor is aware that they have a drug test to complete and they come prepared to try and cheat. In a busy week we may have anywhere from three to 10 cheats."
People also tried adding chemicals such as bleach to urine to try to mask drug use while others took cleansing or flushing pills, which were available at various health stores, he said
"However we still have a number of people fail the test and get quite upset that the flushing product they purchased hasn't worked."
He said the most common drug found in tests which came back positive in Rotorua was cannabis.
Common industries drug testing employees in Rotorua include forestry, construction, transport and horticulture, but Mr Sefton said office workers and hospitality staff were also tested.
Mr Sefton said workplace drug testing options for companies included pre-employment, random testing, post-incident or accident and reasonable cause testing, where an employee is displaying recognised indicators or patterns of drug use.
He said the fact people attempted to cheat workplace drug tests was "a real shame".
"They don't seem to realise, or care, that drug testing is all about providing a safe working environment," he said.
Those caught trying to cheat drug tests were usually fired.
"It is a serious issue when someone is willingly jeopardising safety in the workplace," he said.
Waiariki School of Forestry director Jeremy Christmas said it was not a surprise more Rotorua workplaces were enforcing drug testing of employees.
"I think it is great that this is happening," he said.
"It reduces the risk of any workplace accidents."
Mr Christmas said he had heard of students who had tried to cheat the tests.
"It is a very difficult thing to do. People don't factor in things like temperature and pH tests," he said.
Mr Christmas said he had noticed a decrease in the number of positive results from drug tests.
"When we do get positive results we have noticed that it is generally for cannabis." Additional reporting APN News and Media
